package com.shengruan.common;

import java.util.HashSet;
import java.util.Set;

public class OnlineCounter {
	 private static Set users=new HashSet(); 
	 @SuppressWarnings("unchecked")
	public static void addUser(Visitor user)
	 {

		 users.add(user);
	 }
	 public static void removeUser(Visitor user)
	 {
		 users.remove(user);

	 }

	public static Set getUsers() {
		return users;
	}
}
